Seven types of 3D printing

Previously we mentioned that 3D printing can be divided into 7 categories, including material extrusion, binder jetting, powder bed fusion, material jetting, sheet lamination, directed energy deposition, and stereolithography. Below we will introduce these 7 categories in details.

1. Material Extrusion

The principle of material extrusion is to heat and melt the material, extrude it through a nozzle and accumulate it on the build platform along a preset path, thereby building a solid object layer by layer. Although the most common material is plastic filament, the range of extruded materials is very wide, including metals, ceramics, polymers, concrete, biogels, and even food.

2. Powder Bed Fusion

Powder bed fusion is the process of selectively melting powder particles, such as plastics, metals or ceramics, through thermal energy to build solid objects layer by layer. The process involves laying a thin layer of powder material on the print bed and then using a laser to melt and fuse the powder at specific points on the layer. Then a new layer of powder is laid and combined with the previous layer. This is repeated until the entire object is printed. The final product will be wrapped and supported by unfused powder to avoid the use of additional support structures.

3. Material Jetting

Material jetting is the process of building objects layer by layer by depositing tiny droplets of material on a build plate and solidifying them. The process typically uses photopolymers or waxes, which cure quickly when exposed to light. A notable feature of material jetting is that different materials can be printed on the same object, achieving a mixture of multiple colors and textures. This feature makes the material jetting process ideal for making complex multi-material parts and realistic models.

4. Binder Jetting

Binder jetting is the process of selectively jetting a liquid binder onto a layer of powdered material to bind it together. It combines the features of powder bed fusion and material jetting. Similar to powder bed fusion, binder jetting uses a variety of powdered materials such as metal, plastic, ceramic, wood or sugar; similar to material jetting, it precisely deposits liquid binder into the powder layer via an inkjet head. Regardless of the powder material used, the process of binder jetting is essentially the same, bonding the powder layer by layer until a complete three-dimensional object is built.

5. Sheet Lamination

At its core, the sheet lamination process involves stacking and laminating very thin sheets of material together, layer by layer, to build a 3D object. The stack is then processed into the desired shape by mechanical or laser cutting. The layers of material can be fused together using a variety of methods, including heat, ultrasound, or adhesives, depending on the material, which can range from paper to polymers to metals. When parts are laminated and then laser cut or processed into the desired shape, more waste is generated than with other 3D printing technologies.

6. Directed Energy Deposition

Directed energy deposition is the process of melting and depositing metal materials onto a substrate using a high energy source (such as a laser, electron beam, arc, etc.), building the desired shape layer by layer. Metal powder or metal wire is usually used as the raw material, and because it is similar to the welding process, it can be used to repair, modify or manufacture metal parts.

7. Stereolithography

Stereolithography is a 3D printing process that uses a light source to selectively cure photosensitive resins. It works by precisely irradiating specific points or areas of liquid resin with light to harden it into a solid. After each layer is cured, the build platform moves up or down a small distance (usually between 0.01 and 0.05 mm) and then cures the next layer and connects it to the previous layer. This is repeated layer by layer to form a complete 3D part. After printing, the object usually needs to be cleaned to remove excess liquid resin and post-cured by sunlight or ultraviolet light to enhance the mechanical properties of the object.

The above is an introduction to the seven major types of 3D printing.